CVE-2026-80859

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    CVE-2026-80859

    Published: 4 Sept 2026Last Modified: 15 Sept 2026

    Summary: fuse: fix missing barrier when checking io-uring readiness

    Details: In the Linux kernel, the following vulnerability has been resolved: fuse: fix missing barrier when checking io-uring readiness fuse_block_alloc() reads fch->initialized and then fch->io_uring. fch->io_uring is set before fch->initialized, ordered by the smp_wmb() in fuse_chan_set_intialized(), but fuse_block_alloc() has no matching read barrier between the two loads. This may lead a CPU to observe fch->initialized=1 but fch->io_uring=0, and skip the check that blocks request allocation until the io-uring queues are ready. This can reintroduce the lock-order inversion deadlock that commit 3393ff964e0f prevents. Add an smp_rmb() barrier to pair with the smp_wmb() in fuse_chan_set_initialized() to prevent this.

    References: https://git.kernel.org/stable/c/8974575898cd7a4c818088f102b2e7a0286d3302, https://git.kernel.org/stable/c/dd9c835709f4bb3e4256eea7573e4e6e18f956de, https://git.kernel.org/stable/c/edb310bc27f0ad83e7fd558a3caf1a94ca511654, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80859.json, https://nvd.nist.gov/vuln/detail/CVE-2026-80859, https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 3393ff964e0fa5def66570c54a4612bf9df06b76
    Fixed -8974575898cd7a4c818088f102b2e7a0286d3302

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2026-80859 | CVE-DB